Fluorine-containing compounds

ABSTRACT

A fluorine-containing compound of the formula ##STR1## wherein R f  is a fluoroalkyl ether end group having 5 to 50 carbon atoms, R 1  is an alkyl end group or an aliphatic alkenyl end group, R&#39;&#39;&#39; 2  is an aliphatic alkylene group and R 4  is an aliphatic alkylene group having no or one or more carbon atoms. This fluorine-containing compound can be utilized in magnetic recording media in the form of a lubricant composition.

This is a division of application Ser. No. 07/672,447, filed Mar. 20,1991, now U.S. Pat. No. 5,188,747.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a novel fluorine-containing compounduseful as a lubricant for precision machines and precision parts whichrequire high-precision lubrication, or as a surfactant, a mold-releaseagent, a rust preventive, etc.; a process for producing thefluorine-containing compound; a lubricant composition comprising thefluorine-containing compound; and a magnetic recording medium such as amagnetic tape, a magnetic disk, etc., the lubricant layer of whichcomprises the fluorine-containing compound.

2. Description of the Prior Art

With minuaturization and an increase in precision of machines and partsthereof, the mode of lubrication in their sliding portions has come tobe changed from hydrodynamic lubrication to boundary lubrication.Particularly in electronic machines and electronic parts, for example,VTR and magnetic discs, high-precision lubrication has become necessaryfor sliding a magnetic tape or a magnetic disc on a magnetic head,because of employment of thin ferromagnetic metal films for improvingthe packing density. For example, in metallized tapes and hard discs, alubricant layer on the surface of a magnetic layer is formed to athickness of only several tens angstroms to increase the output byreducing the loss due to the spacing between a magnetic recording mediumand a magnetic head as much as possible while assuring the durabilityand the practical reliability. Therefore, it is an important problem todevelop an organic compound having an excellent lubricating capability,as a material for forming the lubricant layer.

As lubricants for thin-metal-film type magnetic recording medium, thosehaving a fluorocarbon chain in the molecule are excellent incompatibility with thin metal films, and hence there have been proposedvarious fluorocarbon-based lubricants (for instance, Japanese PatentApplication Kokai Nos. 61-107527, 61-107528, 61-107529, 62-92225,62-92226 and 62-92227). In addition, compounds comprising aperfluroalkyl polyether chain have been proposed as lubricants formagnetic recording medium (for instance, U.S. Pat. No. 3,778,308 andJapanese Patent Application Kokai No. 60-109028).

On the other hand, fluorine-containing compounds having the molecularstructure shown below have been proposed as surfactants: ##STR2##wherein R₆ is a hydrogen atom or an aliphatic alkyl group having 1 to 12carbon atoms, R₈ is an aliphatic alkylene group having I, 2 or 5 carbonatoms, and h is zero or an integer of 1 to 8 (U.S. Pat. No. 3,798,265).

The following is an important requirement which a lubricant forthin-metal-film magnetic recording medium should satisfy. The lubricantshould adhere strongly to the surface of the thin metal film or theprotective film of the medium and the surface of a magnetic head to forma coating layer on each of the surfaces, and groups of molecules of thelubricant should easily be sheared from one another on the contact pointof the coating layers, namely, on the surface on which the magneticrecording medium and the magnetic head slide.

Perfluoroalkyl polyethers heretofore well-known as lubricants formagnetic recording medium are good in the ease of shearing betweengroups of molecules because substantially the whole surface of eachmolecule is covered with fluorine atoms. But since the polarity of themolecules is low, the conventional lubricants have a low adhesivestrength to the surface of a thin metal film or a protective film andthe surface of a magnetic head. For removing this defect, there havebeen proposed perfluoroalkyl polyethers having various polar groupsintroduced into the ends of the molecule. But when their molecularweight is 3,000 or more, no sufficient effect of the introduction of thepolar groups can be obtained. On the other hand, when the molecularweight is reduced for enhancing the effect of the polar groups, theinteraction between molecules of the perfluoroalkyl polyether is weak,so that the amount of such a lubricant is decreased by its evaporation.Thus, the perfluoroalkyl polyethers and the terminally modified productsthereof are poor in adhesive properties to the surface of a thin metalfilm or a protective film and the surface of a magnetic head, and instability. Consequently, thin-metal-film type magnetic recording mediaobtained by using these compounds as lubricants have been poor inreliability on durability, in particular, in performance characteristicsin low-humidity circumstances in which the aggregation of a magneticmetal tends to occur on the surface of a magnetic head.

On the other hand, the fluorocarbon-based lubricants disclosed in theabove prior art references have heretofore been used in thin-metal-filmtype magnetic recording media because of their excellent compatibilitywith thin metal films, but have been disadvantageous in that they cannotgive a sufficient durability in a low-humidity circumstance of 10% RH orless.

Conventional processes for producing a fluorine-containing compound aredescribed below.

A process for producing a fluorine-containing alkylsuccinic acidderivative has been proposed in Japanese Patent Application Kokai No.61-257226. Specifically, in this process, the fluorine-containingalkyl-succinic acid derivative is obtained by subjecting a mixture ofequimolar amounts of a higher alcohol having a perfluoroalkyl group andalkylsuccinic anhydride to reaction with heating at 60° to 150° C. inthe atmosphere. This process is effective against perfluoroalkyl group,but has been disadvantageous in that when an alcohol having afluoroalkyl ether group is used in place of the higher alcohol having aperfluoroalkyl group, the yield of the fluorine-containing alkylsuccinicacid derivative is as very low as 10% or less because the reactivity ofthe former alcohol is considerably lower than that of the latteralcohol. Furthermore, this process has been disadvantageous also in thatsince the position of attachment of the fluoroalkyl ether end group toan aliphatic-alkylcarboxylic acid is limited to the carbon atom at the αor β position adjacent to the carboxyl group, there cannot be obtained afluorine-containing compound in which the fluoroalkyl ether end group isattached to any of various positions from α position to ω position.

A process for producing a nitrogen-containing perfluoro(carboxylic acidfluoride) has been proposed in Japanese Patent Application Kokai No.64-70450. Specifically, in this process, aperfluoro(3-dialkylamino-n-butyric fluoride) is obtained byelectrolyzing a reactive derivative of 3-dialkylamino-n-butyric acid inliquid hydrogen fluoride. This process has been disadvantageous not onlyin that both of the two aliphatic hydrocarbon end groups in the moleculeof the product are perfluoroalkyl groups, but also in that it isdifficult to utilize an aliphatic long-chain alkyl group or an aliphaticpolyalkyl oxide group.

A process for producing a phthalic acid diester having aperfluorobutenyloxy group has been proposed in Japanese PatentApplication Kokai No. 61-24547. Specifically, in this invention, thephthalic acid diester having a perfluorobutenyloxy group is obtained byadding 2 to 20 moles of an aliphatic alcohol having an alkyl grouphaving 1 to 15 carbon atoms and 0.01 to 1 mole of concentrated sulfuricacid per mole of a phthalic anhydride derivative having aperfluorobutenyloxy group, and carrying out the reaction with refluxingthe alcohol or at 100° to 150° C. for 30 minutes to 24 hours. Thisprocess has been disadvantageous not only in that both reactive groupsof the acid anhydride becomes ester linkage groups, but also in that afluoroalkyl ether group cannot be utilized because a fluoroalkyl groupas the end group is limited to perfluorobutenyloxy group.

A process for producing a perfluoroalkyl-substituted half ester or aperfluoroalkyl-substituted half amide has been proposed in JapanesePatent Application Kokai No. 54-84524. Specifically, in this process,the perfluoroalkyl-substituted half ester of half amide is obtained byreacting maleic anhydride with a hydroxy-substituted oramino-substituted nonionic compound (e.g. an aliphatic alkyl alcohol oran aliphatic alkyl amine) at room temperature or at 50° to 100° C. toobtain a maleic acid half ester or a maleic acid half amide, and thenadding a perfluoroalkylalkylene thiol to the thus obtained half ester orhalf amide at 30° to 75° C. in the presence of a base catalyst. Theperfluoroalkyl-substituted half ester or half amide can be obtained alsobe reversing the order of the above reactions. These processes have beendisadvantageous in that the product obtained by them is a mixture ofcompounds having a thioether linkage group to the carbon atom at the αor β, respectively, position adjacent to the carboxyl group, so thatthere cannot be obtained a single fluorine-containing compound having athioether linkage group only to the carbon atom at the α position.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a novelfluorine-containing compound which imparts a high reliability ondurability to thin-metal-film type magnetic recording media in allcircumstances including low-humidity circumstances; a lubricantcomposition comprising the fluorine-containing compound; and a magneticrecording medium such as a magnetic tape, a magnetic disc, etc., thelubricant layer of which comprises the fluorine-containing compound.

In order to achieve this object, the present inventors conducted variousresearches in consideration of the problems in the prior art andconsequently have found that a fluorine-containing compound having inthe molecule a fluoroalkyl ether end group, an aliphatic hydrocarbon endgroup and a specific polar end group is most suitable as a lubricant forthin-metal-film type magnetic recording medium. The present inventionwas made on the basis of such finding and a novel production process.

The present invention relates to fluorine-containing compoundsrepresented by the general formula [I]: ##STR3## wherein R_(f) is afluoroalkyl ether end group having 5 to 50 carbon atoms, R₁ is analiphatic alkyl end group or an aliphatic alkenyl end group, R₂ is analiphatic alkylene group or an aliphatic polyalkylene oxide group whichhave no or one or more carbon atoms, each of R₃ and R₄ is an aliphaticalkylene group having no or one or more carbon atoms, X is a connectinggroup selected from the group consisting of

    --COOR.sub.5 -- and --CON(R.sub.6)--

(wherein R₅ is an aliphatic alkylene group having no or one or morecarbon atoms, and R₆ is a hydrogen atom or an aliphatic alkyl grouphaving 1 to 12 carbon atoms), each of W and Y is a connecting groupselected from the group consisting of

    --S--, --COO-- and --SCH.sub.2 CH(R.sub.7)COO--

(wherein R₇ is a hydrogen atom or a methyl group), Z is a connectinggroup selected from the group consisting of ##STR4## and each of l, mand n is zero or 1.

More specifically, the present invention relates to fluorine-containingcompounds represented by the following general formulas [II], [III],and[VII] to [X]: ##STR5## wherein R_(f) is a fluoroalkyl ether end grouphaving 5 to 50 carbon atoms, R₁ is an aliphatic alkyl end group or analiphatic alkenyl end group, R'₂ is an aliphatic alkylene group or analiphatic polyalkylene oxide group, X is a connecting group selectedfrom the group consisting of

    --COOR.sub.5 -- and --CON(R.sub.6)--

(wherein R₅ is an aliphatic alkylene group having no or one or morecarbon atoms, and R₆ is a hydrogen atom or an aliphatic alkyl grouphaving 1 to 12 carbon atoms), and each of m and n is zero or 1; ##STR6##wherein R_(f) is a fluoroalkyl ether end group having 5 to 50 carbonatoms, R₁ is an aliphatic alkyl end group or an aliphatic alkenyl endgroup, each of R''₂ and R₄ is an aliphatic alkylene group having no orone or more carbon atoms, X' is a connecting group selected from thegroup consisting of

    --COOR'.sub.5 -- and --CON(R.sub.6)--

(wherein R'₅ is an aliphatic alkylene group, and R₆ is a hydrogen atomor an aliphatic alkyl group having 1 to 12 carbon atoms), and m is zeroor 1; ##STR7## wherein R_(f) is a fluoroalkyl ether end group having 5to 50 carbon atoms, R₁ is an aliphatic alkyl end group or an aliphaticalkenyl end group, R'''₂ is an aliphatic alkylene group, and R₄ is analiphatic alkylene group having no or one or more carbon atoms; ##STR8##wherein R_(f) is a fluoroalkyl ether end group having 5 to 50 carbonatoms, R₁ is an aliphatic alkyl end group or an aliphatic alkenyl endgroup, R'₂ is an aliphatic alkylene group or an aliphatic polyalkyleneoxide group, X is a connecting group selected from the group consistingof

    --COOR.sub.5 -- and --CON(R.sub.6)--

(wherein R₅ is an aliphatic alkylene group having no or one or morecarbon atoms, and R₆ is a hydrogen atom or an aliphatic alkyl grouphaving 1 to 12 carbon atoms), Z' is a connecting group represented bythe formula: ##STR9## and m is zero or 1; ##STR10## wherein R_(f) is afluoroalkyl ether end group having 5 to 50 carbon atoms, R₁ is analiphatic alkyl end group, R'₂ is an aliphatic alkylene group or analiphatic polyalkylene oxide group, X is a connecting group selectedfrom the group consisting of

    --COOR.sub.5 -- and --CON(R.sub.6)--

(wherein R₅ is an aliphatic alkylene group having no or one or morecarbon atoms, and R₆ is a hydrogen atom or an aliphatic alkyl grouphaving 1 to 12 carbon atoms), and each of m and n is zero or 1;##STR11## wherein R_(f) is a fluoroalkyl ether end group having 5 to 50carbon atoms, R'₁ is an aliphatic alkyl end group, R'₂ is an aliphaticalkylene group or an aliphatic polyalkylene oxide group, R₇ is ahydrogen atom or a methyl group, X is a connecting group selected fromthe group consisting of

    --COOR.sub.5 -- and --CON(R.sub.6)--

(wherein R₅ is an aliphatic alkylene group having no or one or morecarbon atoms, and R₆ is a hydrogen atom or an aliphatic alkyl grouphaving 1 to 12 carbon atoms), and m is zero or 1;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The end groups of the fluorine-containing compounds of the presentinvention include, for example, the groups described below.

The aliphatic hydrocarbon end groups, i.e., the aliphatic alkyl endgroup and the aliphatic alkenyl end group, include, for example,

    C.sub.i H.sub.2i+1 -

    C.sub.i H.sub.2i-1 - ##STR12## wherein each of i and j is an integer of 6 or more, and k is zero or an integer of 1 or more. The number of carbon atoms of each of these end groups is suitably 6 to 30 (preferably 10 to 26). When it is 5 or less, or 31 or more, the lubricating properties are deteriorated.

The fluoroalkyl ether end group includes ##STR13## wherein p is aninteger of 1 to 15, and q is an integer of 1 to 45. The number of carbonatoms of each of these end groups is suitably 50 or less (preferably 40or less). When it is 51 or more, the effect of the polar end group islessened.

Processes for producing the fluorine-containing compounds of the presentinvention are explained below.

A fluorine-containing compound of the general formula [II] can beproduced in high yield by subjecting a mixture of equimolar amounts ofan aliphatic-alkylsuccinic anhydride or an aliphatic-alkenylsuccinicanhydride and an alcohol having an fluoroalkyl ether group to additionreaction with heating at 100° to 150° C., at a pressure of 3 kg/cm² ormore in an autoclave. As to this addition reaction, a conventionalmethod in which the reaction is carried out at atmospheric pressuregives a very low yield. In the present invention, a high yield can beobtained by finding out a method in which as described above, thereaction is carried out under pressure. In this case, a pressure of atleast 3 kg/cm² is required.

A fluorine-containing compound of the general formula [III] can beobtained by adding a carboxylic acid halide having a fluoroalkyl ethergroup to a mixed solution of an aliphatic-alkyl oxy-acid or analiphatic-alkenyl oxy-acid and a base such as triethylamine or pyridine(as a solvent, the base itself or an aprotic anhydrous solvent such asanhydrous benzene or anhydrous ether is suitable) slowly withice-cooling so as to make the amount of the acid halide equimolar withthat of the oxy-acid, subjecting the reactive group of the acid halideand the hydroxyl group of the oxy-acid to esterification, and capturingand removing secondarily produced hydrochloric acid by means of thebase.

As to a method for attaching a fluoroalkyl ether group to the hydroxylgroup of an oxy-acid, when esterification is carried out by the use of acarboxylic acid having a fluoroalkyl ether group and a conventional acidcatalyst at a high temperature, the carboxyl group of the oxy-acidinhibits this reaction, so that the fluoroalkyl group cannot be attachedto the hydroxyl group of the oxy-acid. Thus, the present inventors havefound that this esterification can be allowed to proceed only by amethod in which a carboxylic acid halide having a fluoroalkyl group isused and the reaction is carried out at a low temperature. This findingenabled the production of the fluorine-containing compound of thepresent invention.

A fluorine-containing compound of the general formula [VII] can beproduced by adding an aqueous solution of an weak alkali such as sodiumcarbonate or potassium carbonate to a mixed solution carbonate orpotassium carbonate to a mixed solution of equimolar amounts of asecondary alkylamine having a fluoroalkyl ether group and aω-haloalkylcarboxylic acid ester (as a solvent, a hydrophilic solventsuch as acetone or methyl ethyl ketone is suitable), refluxing theresulting mixture with heating to induce dehalogenation andnitrogen-carbon bonding reaction, and then subjecting the ester linkagegroup to hydrolysis with a strong alkali to make one of the end groupsinto a carboxyl group. In the dehalogenation, a carboxyl group inhibitsthe attack of the ω-haloalkyl group against the imino group because ofits high affinity for the imino group. Thus, the present inventors havefound that since the presence of a carboxyl group inhibits thedehalogenation, the nitrogen-carbon bonding reaction can be allowed toproceed by masking the carboxyl group, for example, by subjecting thecarboxyl group to esterification. This finding also enabled theproduction of the fluorine-containing compound of the present invention.

A fluorine-containing compound of the general formula [VIII] can beproduced by adding an alcohol having a fluoroalkyl ether group to amixed solution of trimellitic anhydride chloride and a base such astriethylamine or pyridine (as a solvent, the base itself or an aproticanhydrous solvent such as anhydrous benzene or anhydrous ether issuitable) slowly with ice-cooling so as to make the amount of thealcohol equimolar with that of trimellitic anhydride chloride, capturingand removing secondarily produced hydrochloric acid by means of the baseto obtain a trimellitic anhydride fluoroalkyl ether ester, adding to theester an alcohol having an aliphatic hydrocarbon group in an amountequimolar with the amount of the ester and an aprotic anhydrous solventsuch as anhydrous benzene or anhydrous n-heptane, refluxing theresulting mixture with heating at 70° to 140° C. to subject the reactivegroup of the acid anhydride to ester-addition reaction with the alcoholhaving an aliphatic hydrocarbon group. The esterification of thetrimellitic anhydride chloride is carried out by subjecting the reactivegroup of acid anhydride to a second-stage reaction after subjecting thereactive group of acid chloride to a first-stage reaction. By thesereaction, different alcohol moieties can be introduced into the samemolecule through ester linkages. Moreover, one of the carbonyl groups,i.e., the reactive groups of acid anhydride becomes carboxyl end group.Thus, the present inventors have found that in the second-stagereaction, the alcohol attached through an ester linkage by thefirst-stage reaction does not undergo hydrolysis andtransesterification. This finding also enabled the production of thefluorine-containing compound of the present invention.

A fluorine-containing compound of the general formula [IX] can beproduced in high yield by subjecting a mixture of equimolar amounts ofthiomalic anhydride having an aliphatic alkyl group and an alcoholhaving a fluoroalkyl ether group to addition reaction with heating at100° to 150° C., at a pressure of 3 kg/cm² or more in an autoclave. Asto this addition reaction, a conventional method in which the reactionis carried out at atmospheric pressure gives a very low yield. In thepresent invention, a high yield can be obtained by finding out a methodin which, as described above, the reaction is carried out underpressure. In this case, a pressure of at least 3 kg/cm² is required.

A fluorine-containing compound of the general formula [X] can beproduced by adding a base catalyst such as sodium acetate,triethylamine, or pyridine and a polymerization inhibitor such ashydroquinone to a mixed solution of equimolar amounts of an α-mercaptoaliphatic-alkylcarboxylic acid and an acrylate or a methacrylate whichhave a fluoroalkyl ether group (as a solvent, a hydrophilic solvent suchas ethanol or methyl ethyl ketone is suitable), and refluxing theresulting mixture with heating to add a group having a carbon-carbondouble bond, i.e., an acryl or methacryl group to the mercapto group.The addition reaction of an aliphatic-alkylthiol to analiphatic-alkylolefin has heretofore been well known [as literature onthis reaction, there is, for example, "Yuki lo Kagaku-Gosei Hanno Hen(Organic sulfur Chemistry-Synthetic Reaction)" p. 33, Kagaku Dojin K.K.,(1982)]. The present inventor have found that also when an α-mercaptoaliphatic-alkylcarboxylic acid is used as a thiol, the above additionreaction proceeds without inhibition by the carboxyl group. This findingalso enabled the production of the fluorine-containing compound of thepresent invention.

As the starting fluoroalkyl ethers used for producing thefluorine-containing compounds of the present invention, there are, forexample, the compounds described below.

The alcohol having a fluoroalkyl ether group includes, for example,##STR14## wherein R₆ is a hydrogen atom or an aliphatic alkyl grouphaving 1 to 12 carbon atoms, R'''₂ is an aliphatic alkylene group, p isan integer of 1 to 15, q is an integer of 1 to 45, and r is an integerof 1 or more.

The carboxylic acid halide having a fluoroalkyl ether group includes,for example, ##STR15## wherein R₆ is a hydrogen atom or an aliphaticalkyl group having 1 to 12 carbon atoms, R'''₂ is an aliphatic alkylenegroup, X is a fluorine atom or a chlorine atom, p is an integer of 1 to15, and q is an integer of 1 to 45.

The secondary alkylamine having a fluoroalkyl ether group includes, forexample, ##STR16## wherein R₁ is an aliphatic alkyl end group or analiphatic alkenyl end group, p is an integer of 1 to 15, and q is aninteger of 1 to 45.

The acrylate having a fluoroalkyl ether group includes, for example,##STR17## wherein R₆ is a hydrogen atom or an aliphatic alkyl grouphaving 1 to 12 carbon atoms, R'''₂ is an aliphatic alkylene group, p isan integer of 1 to 15, q is an integer of 1 to 45, and r is an integerof 1 or more.

The methacrylate having a fluoroalkyl ether group includes, for example,##STR18## wherein R₆ is a hydrogen atom or an aliphatic alkyl grouphaving 1 to 12 carbon atoms, R'''₂ is an aliphatic alkylene group, p isan integer of 1 to 15, q is an integer of 1 to 45, and r is an integerof 1 or more.

As the lubricant compositions of the present invention, mixtures of afluorine-containing compound of the general formula [I] and anotherlubricant are suitable. As the another lubricant, fluorocarbon typelubricants are preferably used. The fluorine-containing compound of thegeneral formula [I] can be used alone as an lubricant. In particular,the fluorocarbon type lubricants described, for example, in JapanesePatent Application Kokai Nos. 61-107527, 61-107528, 61-107529, 62-92225,62-92226 and 62-92227 are suitable. In addition, other conventionallubricants, rust preventives, etc. can be used in admixture with thefluorine-containing compound of the general formula [I].

The fluorine-containing compound of the general formula [I] should becontained in the lubricant composition in a proportion of 20% or more,preferably 30% or more. When its content is less than 20%, the effect ofthe present invention can hardly be obtained.

Next, there are explained below examples of thinferromagnetic-metal-film type magnetic recording medium obtained byforming a lubricant layer comprising the fluorine-containing compound ofthe general formula [I].

The above-mentioned lubricant composition is applied on the magneticlayer of a thin-ferromagnetic-metal-film type magnetic recording mediumdirectly or with a protective layer between by a conventional wetcoating method or a dry coating method such as vacuum deposition. As tothe amount of coating, the composition is applied in the form of a thinlayer in an amount of 0.05 to 100 mg, preferably 0.1 to 50 mg, per m² ofthe surface.

As the thin ferromagnetic metal film, there can be used thin films ofCo, Co-Ni, Co-Cr, Co-Fe, Co-Ni-Cr, Co-Ni-Fe, Co-Ni-P, Co-Ni-Ta and thelike, and a partially oxidized product thereof. These thin films areformed by vacuum deposition, sputtering, ion plating, plating, etc. Ifnecessary, a primer layer of Cr, Ti or the like can be formed. Thethickness of the thin ferromagnetic metal film including the thicknessof the primer layer is suitably 500 to 5,000 Å. On the surface of thethin ferromagnetic metal film, there can optionally be formed, forexample, a metallic protective layer of Cr, W, NiP or the like; aninorganic protective layer of SiO, SiC, carbon, graphite, diamond-likecarbon or the like; an organic protective layer of a fluororesin,silicone resin, epoxy resin, polyamide resin, plasma polymerizationproduct, radiation polymerization product or the like; or a compositeprotective layer.

As a non-magnetic substrate, there can be used those composed mainly ofan oxide such as glass, ceramics or the like; a metal such as Al alloy,Ti alloy or the like; or a plastic such as polyester, polyimide,polyamide-imide, polycarbonate, polyacrylate or the like. In addition,there can be used substrates obtained by optionally forming a Co-Pplated film, a polyimide coating film or the like on the surface of anyof these materials, and substrates obtained by optionally forming, forexample, protuberances in the form of fine particles, hills, waves orthe like, or by texturing. The surface roughness of the substrates issuitably 50 to 600 Å in terms of maximum height (R max.). As theirshape, for example, tape, film, sheet, disc, card and drum shapes can bechosen depending on purposes.

The fluorine-containing compounds of the present invention have in themolecule a fluoroalkyl ether end group, an aliphatic hydrocarbon endgroup and a specific polar end group, and their molecular weight ishundreds to about 3,000. Therefore, the effect of the polar end group issufficiently brought about and the polar end group adheres strongly tothe surface of the thin metal film or the protective film and thesurface of a magnetic head. In addition, the fluoroalkyl ether end groupis exposed at the surface of the lubricant layer to contribute to thereduction of the surface energy and make the surface not adhesive.Furthermore, the aliphatic hydrocarbon end group has a flexiblecarbon-carbon chain, and molecules of the compound are oriented by themoderate intermolecular interaction with the hydrocarbon chains ofadjacent molecules, so that the compound has satisfactory lubricatingproperties.

Accordingly, by virtue of these synergistic effects of the end groups, asatisfactory lubricating capability is exhibited in all circumstancesincluding low-humidity circumstances. Therefore, the problems in thereliability on durability of a thin-metal-film type magnetic recordingmedium are solved.

As described above, the fluorine-containing compounds of the presentinvention can be utilized not only singly but also in the form of alubricant composition comprising a mixture of the fluorine-containingcompound and a conventional compound. Moreover, they can be utilized forproducing a magnetic recording medium comprising a lubricant layercomprising the fluorine-containing compound. Therefore, their industrialvalue is very high.

In Examples 1 to 49, there are specifically described examples offluorine-containing compound and processes for producing the same. InExamples 50 to 112, there are specifically described examples ofmagnetic recording medium obtained by using a lubricant compositioncomprising each of the fluorine-containing compounds.

However, the present invention should not be construed to be restrictedby these examples.

EXAMPLE 1 ##STR19##

In a 1 -liter pressure autoclave made of glass having an agitating bladewere placed 64.8 (0.10 mole) of an alcohol having a fluoroalkyl ethergroup represented by the formula F--CF(CF₃)CF₂ O]₃ CF(CH₃)CH₂ OH and35.3 g (0.10 mole) of octadecylsuccinic anhydride. The air in the systemwas replaced with nitrogen, after which the reaction was carried outwith stirring at 120° C. and at a nitrogen pressure of 3 kg/cm² for 5hours. Then, the reaction mixture was dissolved in isopropyl ether, andthe resulting solution was cooled to -10° C. to remove the unreactedoctadecylsuccinic anhydride. Subsequently, the residue was transferredto a vacuum distillation still provided with an oil diffusion pump andthe unreacted alcohol having a fluoroalkyl ether group was removed underconditions of 100° C. and about 1×10⁻³ mmHg to obtain 92 g (yield 92%)of a white solid having a melting point of 86° C. As a result ofinfrared spectroscopic analysis (IR), gel permeation chromatography(GPC) and field desorption mass spectrometry (FD-MS), the while solidwas found to be a mixture of fluorine-containing compounds of theformulas A and A' which did not contain the starting materials and anyby-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm¹ and an absorption peak due to an ester at 1,755 cm⁻¹. An absorptionpeak due to the acid anhydride at 1,775 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group and octadecylsuccinic anhydride.

FD-MS; A parent peak appeared at a m/e ratio of 1,000.

EXAMPLE 2 ##STR20##

In a 1-liter pressure autoclave made of glass having an agitating bladewere placed 70.0 g (0.10 mole) of an alcohol having a fluoroalkyl ethergroup represented by the formula CF₃ O--CF₂ CF(CF₃)O]_(p)[CF₂ O]_(g) CF₂CH₂ OH wherein each of p and q is an integer of 1 to 9 (averagemolecular weight: 700) and 29.7 g (0.10 mole) of tetradecylsuccinicanhydride. The air in the system was replaced with nitrogen, after whichthe reaction was carried out with stirring at 100° C. and at a nitrogenpressure of 5 kg/cm² for 6 hours. Then, the resulting mixture wasdissolved in isopropyl ether and the resulting solution was cooled to-10° C. to remove the unreacted tetradecylsuccinic anhydride.Subsequently, the residue was transferred to a vacuum distillation stillprovided with an oil diffusion pump, and the unreacted alcohol having afluoroalkyl ether group was removed under conditions of 100° C. andabout 1×10⁻³ mmHg to obtain 96 g (yield 96%) of a white solid having amelting point of 60° C. As a result of IR, GPC and FD-MS, the whilesolid was found to be a mixture of fluorine-containing compounds of theformulas B and B' which did not contain the starting materials and anyby-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm¹ and an absorption peak due to an ester at 1,755 cm⁻¹. An absorptionpeak due to the acid anhydride at 1,775 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group and octadecylsuccinic anhydride.

FD-MS; A parent peak appeared at a m/e ratio of 1,000.

EXAMPLE 3 ##STR21##

In a 1 -liter pressure autoclave made of glass having an agitating bladewere placed 248 g (0.10 mole) of an alcohol having a fluoroalkyl ethergroup represented by the formula F--C₃ F₆ O)_(p) C₂ F₄ CH₂ OH wherein pis an integer of 1 to 15 (average molecular weight: 2,480) and 35.0 g(0.10 mole) of octadecenylsuccinic anhydride. The air in the system wasreplaced with nitrogen, after which the reaction was carried out withstirring at 140° C. and at a nitrogen pressure of 10 kg/cm² for 8 hours.Then, the reaction mixture was dissolved in isopropyl ether and theresulting solution was cooled to -10° C. to remove the unreactedoctadecenylsuccinic anhydride. Subsequently, the residue was transferredto a vacuum distillation still provided with an oil diffusion pump andthe unreacted alcohol having a fluoroalkyl ether group was removed underconditions of 140° C. and about 1×10⁻⁴ mmHg to obtain 232 g (yield 82%)of a wax-like semisolid. As a result of IR, GPC and FD-MS, the wax-likesemisolid was found to be a mixture of fluorine-containing compounds ofthe formulas C and C' which did not contain the starting materials andany by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm¹ and an absorption peak due to an ester at 1,755 cm⁻¹. An absorptionpeak due to the acid anhydride at 1,775 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group and octadecylsuccinic anhydride.

FD-MS; A parent peak appeared at a m/e ratio of 2,830.

EXAMPLE 4 ##STR22##

132 Grams (yield 87%) was a colorless and transparent liquid wasproduced under the same conditions as in Example 1, except for using 128g (0.10 mole) of an alcohol having a fluoroalkyl ether group representedby the formula CClF₂ O--CF₂ CF(CF₃)O]_(p) [CF₂ O]_(q) CF₂ CH₂ OH whereineach of p and q is an integer of 1 to 15 (average molecular weight:1,280) and 24.0 g (0.10 mole) of decylsuccinic anhydride as startingmaterials. As a result of IR, GPC and FD-MS, the colorless andtransparent liquid was found to be a mixture of fluorine-containingcompounds of the formulas D and D' which did not contain the startingmaterials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻¹. An absorptionpeak due to the acid anhydride at 1,775 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group and octadecylsuccinic anhydride.

FD-MS; A parent peak appeared at a m/e ratio of 1,520.

EXAMPLE 5

The following fluorine-containing compounds were produced under the sameconditions as in Example 1. ##STR23##

EXAMPLE 6

The following fluorine-containing compounds were produced under the sameconditions as in Example 1. ##STR24##

EXAMPLE 7

The following fluorine-containing compounds were produced under the sameconditions as in Example 1. ##STR25##

EXAMPLE 8

The following fluorine-containing compounds were produced under the sameconditions as in Example 1. ##STR26##

EXAMPLE 9 ##STR27##

In a 1-liter flask equipped with an agitating blade and a droppingfunnel were placed 66.4 g (0.10 mole) of a carboxylic acid fluoridehaving a fluoroalkyl ether group represented by the formulaF--CF(CF₃)CF₂ O]₃ CF(CF₃)COF and 300 ml of anhydrous diethyl ether, andcooled to 5° C. or lower. Then, a solution of 27.2 g (0.10 mole) ofα-hydroxypalmitic acid in 100 ml of anhydrous pyridine was addeddropwise with stirring over a period of about 2 hours to carry out thereaction. After completion of the reaction, the reaction solution waswashed with 5 % hydrochloric acid. Subsequently, it was repeatedlywashed with distilled water until the pH of the aqueous layer became 7.The solution thus washed was dried over anhydrous sodium sulfate. Then,the resulting solution was cooled to -10° C. to remove the unreactedα-hydroxypalmitic acid. The residue was transferred to a vacuumdistillation still provided with an oil diffusion pump, and a carboxylicacid having a fluoroalkyl ether group produced from the unreactedstarting carboxylic acid fluoride having a fluoroalkyl ether group byhydrolysis was removed under conditions of 100° C. and about 1×10⁻³ mmHgto obtain 60 g of a white solid having a melting point of 76° C. As aresult of IR, GPC and FD-MS, the white solid was found to be afluorine-containing compound of the formula E which did not contain thestarting materials and any by-product.

IR; An absorption peak due to an ester at 1,755 cm⁻¹ appeared. Anabsorption peak due to a hydroxyl group at 3,330 cm⁻¹ disappeared.

GPC; There were not detected the carboxylic acid having a fluoroalkylether group and α-hydroxypalmitic acid, the starting materials.

FD-MS; A parent peak appeared at a m/e ratio of 917.

EXAMPLE 10 ##STR28##

In a 1-liter flask equipped with an agitating blade and a droppingfunnel were placed 75.0 g (0.10 mole) of a carboxylic acid chloridehaving a fluoroalkyl ether group represented by the formula CF₃ O--CF₂CF(CF₃)O]_(p) [CF₂ O]_(q) CF₂ COCl wherein each of p and q is an integerof 1 to 9 (average molecular weight: 750) and 300 ml of anhydrousdiethyl ether, and cooled to 5° C. or lower. Then, a solution of 30.1 g(0.10 mole) of 12 -hydroxystearic acid in 100 ml of anhydrous pyridinewas added dropwise with stirring over a period of about 2 hours to carryout the reaction. After completion of the reaction, the same purifyingtreatment as in Example 9 was carried out to obtain a white solid (72 g)having a melting point of 62° C. As a result of IR, GPC and FD-MS, thewhite solid was found to be a fluorine containing compound of theformula F which did not contain the starting materials and anyby-product.

IR; An absorption peak due to an ester at 1,755 cm⁻¹ appeared. Anabsorption peak due to a hydroxyl group at 3,330 cm⁻¹ disappeared.

GPC; There were not detected carboxylic acid having a fluoroalkyl ethergroup and 12-hydroxystearic acid, the starting materials.

FD-MS; A parent peak appeared at a m/e ratio of 1,010.

EXAMPLE 11 ##STR29##

In a 1-liter flask equipped with an agitating blade and a droppingfunnel were placed 30.0 g (0.10 mole) of 9-oxy-12-octadecenoic acid and300 ml of anhydrous pyridine, and cooled to 5° C. or lower. Then, asolution prepared by dissolving 251 g (0.10 mole) of a carboxylic acidchloride having a fluoroalkyl ether group represented by the formulaF--C₃ F₆ O)_(p) C₂ F₄ COCl wherein p is an integer of 1 to 15 (averagemolecular weight: 2,510) in 300 ml of anhydrous diethyl ether, was addeddropwise with stirring over a period of about 3 hours to carry out thereaction. After completion of the reaction, the same purifying treatmentas in Example 9 was carried out to obtain a wax-like semisolid (166 g).As a result of IR, GPC and FD-MS, the wax-like semisolid was found to bea fluorine-containing compound of the formula G which did not containthe starting materials and any by-product.

IR; An absorption peak due to an ester at 1,755 cm⁻¹ appeared. Anabsorption peak due to a hydroxyl group at 3,330 cm⁻¹ disappeared.

GPC; There were not detected carboxylic acid having a fluoroalkyl ethergroup and 9-oxy-12-octadecenoic acid, the starting materials.

FD-MS; A parent peak appeared at a m/e ratio of 2,770.

EXAMPLE 12 ##STR30##

A colorless and transparent liquid was produced under the sameconditions as in Example 9, except for using a carboxylic acid chloridehaving a fluoroalkyl ether group represented by the formula CClF₂ O--CF₂CF(CF₃)O]_(p) [CF₂ O]_(q) CF₂ COCl wherein each of p and q is an integerof 1 to 15 (average molecular weight: 1,310) and β-hydroxymyristic acidas starting materials. As a result of IR, GPC and FD-MS, the colorlessand transparent liquid was found to be a fluorine-containing compound ofthe formula H which did not contain the starting materials and anyby-product.

IR; An absorption peak due to an ester at 1,755 cm⁻¹ appeared. Anabsorption peak due to a hydroxyl group at 3,330 cm⁻¹ disappeared.

GPC; There were not detected carboxylic acid having a fluoroalkyl ethergroup and β-hydroxymyristic acid, the starting materials.

FD-MS; A parent peak appeared at a m/e ratio of 1,550.

EXAMPLE 13

The following fluorine-containing compound was produced under the sameconditions as in Example 9. ##STR31##

EXAMPLE 14

The following fluorine-containing compound was produced under the sameconditions as in Example 9. ##STR32##

EXAMPLE 15

The following fluorine-containing compound was produced under the sameconditions as in Example 9. ##STR33##

EXAMPLE 16 ##STR34##

In a 1-liter flask equipped with an agitating blade and a droppingfunnel were placed 99.0 g (0.10 mole) of a secondary alkylamine having afluoroalkyl ether group represented by the formula F--CF(CF₃)CF₂ O]₃CF(CF₃)CH₂ NHC₁₈ H₃₇, 21.4 g (0.10 mole) of methyl 3-iodopropionate and300 ml of methyl ethyl ketone (MEK). A solution of 15.9 g of sodiumcarbonate in 100 ml of distilled water was added dropwise with stirringover a period of about 1 hour while raising the temperature. Then,refluxing and stirring were continued for another 8 hours to completethe reaction. After completion of the reaction, the MEK was removed fromthe reaction solution by distillation, and hexane was added to theresidue to obtain a solution. This solution was repeatedly washed withdistilled water until the pH of the aqueous layer became 7. The washedsolution was dried over anhydrous sodium sulfate. Next, the hexane wasdistilled off and the residue was dissolved in isopropyl ether (IEP).The resulting solution was cooled to 5° C. to remove the unreactedsecondary alkylamine having a fluoroalkyl ether group. Then, the IPE wasdistilled off and the residue was dissolved in methanol. The resultingsolution was cooled to 0° C. to remove the unreacted methyl3-iodopropionate. In a 1-liter flask equipped with an agitating bladeand a dropping funnel were placed 59.2 g (0.06 mole) of the thusobtained methyl ester of fluorine-containing compound of the formula Jand a solution of 13.0 g of sodium hydroxide in 150 ml of 90% ethanol.Refluxing and stirring were continued for 3 hours, after which 6Nhydrochloric acid was added until the reaction solution became acidic,whereby a precipitate was formed. The precipitate was dissolved inchloroform and the resulting solution was repeatedly washed withdistilled water until the pH of the aqueous layer became 7. The washedsolution was dried over anhydrous sodium sulfate. Then, the chloroformwas distilled off, after which hexane was added to the residue to obtaina solution of the reaction product in hexane, and recrystallization wascarried out at room temperature to obtain 52 g of a white solid having amelting point of 110° C. As a result of IR, GPC and FD-MS, the whitesolid was found to be the fluorine-containing compound of the formula Jwhich did not contain the starting materials and any by-product.

IR; An absorption peak due to a carboxylic acid at 1,710 cm⁻¹ appeared.

GPC; There were not detected the stating materials, i.e., the secondaryalkylamine having a fluoroalkyl ether group and methyl 3-iodopropionate.

FD-MS; A parent peak appeared at a m/e ratio of 972.

EXAMPLE 17 ##STR35##

In a 1-liter flask equipped with an agitating blade and a droppingfunnel were placed 89.0 g (0.10 mole) of a secondary alkylamine having afluoroalkyl ether group represented by the formula CF₃ O--CF₂CF(CF₃)O]_(p) [CF₂ O]_(q) CF₂ CH₂ NHC₁₄ H₂₉ wherein each of p and q isan integer of 1 to 9 (average molecular weight: 890), 20.0 g (0.10 mole)of methyl iodoacetate and 300 ml of (MEK). A solution of 15.9 g ofsodium carbonate in 100 ml of distilled water was added dropwise withstirring over a period of about 1 hour while raising the temperature.Then, refluxing and stirring were continued for another 8 hours tocomplete the reaction. After completion of the reaction, the samepurifying treatment as in Example 16 was carried out. In a 1-liter flaskequipped with an agitating blade and a dropping funnel were placed 57.7g (0.06 mole) of the thus obtained methyl ester of a fluorine-containingcompound of the formula K and a solution of 13.0 g of sodium hydroxidein 150 ml of 90% ethanol. Refluxing and stirring were conducted for 3hours, after which 6N hydrochloric acid was added dropwise until thereaction solution became acidic, whereby a precipitate was formed. Theprecipitate was subjected to the same purifying treatment as in Example16 to obtain 50 g of a white solid having a melting point of 85° C. As aresult of IR, GPC and FD-MS, the white solid was found to be thefluorine-containing compound of the formula K which did not contain thestarting materials and any by-product.

IR; An absorption peak due to a carboxylic acid at 1,710 cm⁻¹ appeared.

GPC; There were not detected the stating materials, i.e., the secondaryalkylamine having a fluoroalkyl ether group and methyl iodoacetate.

FD-MS; A parent peak appeared at a m/e ratio of 950.

EXAMPLE 18 ##STR36##

A wax-like semisolid was obtained by the same production process as inExample 16, except for using a secondary alkylamine having a fluoroalkylether group represented by the formula F--C₃ F₆ O)_(p) C₂ F₄ CH₂ NHC₁₈H₃₅ wherein p is an integer of 1 to 15 (average molecular weight: 2,730)and methyl 12-bromododecanoate as starting materials. As a result of IR,GPC and FD-MS, the wax-like semisolid was found to be afluorine-containing compound of the formula L which did not contain thestarting materials and any by-product.

IR; An absorption peak due to a carboxylic acid at 1,710 cm⁻¹ appeared.

GPC; There were not detected the starting materials, i.e., the secondaryalkylamine having a fluoroalkyl ether group and methyl12-bromododecanoate.

FD-MS; A main peak appeared at a m/e ratio of 2930.

EXAMPLE 19 ##STR37##

A wax-like semisolid was obtained by the same production process as inExample 16, except for using a secondary alkylamine having a fluoroalkylether group represented by the formula CClF₂ O--CF₂ CF(CF₃)O]_(p) [CF₂O]_(q) CF₂ CH₂ NHC₁₀ H₂₁ wherein each of p and q is an integer of 1 to15 (average molecular weight: 1,420) and methyl 6-iodohexanoate asstarting materials. As a result of IR, GPC and FD-MS, the wax-likesemisolid was found to be a fluorine-containing compound of the formulaM which did not contain the starting materials and any by-product.

IR; An absorption peak due to a carboxylic acid at 1,710 cm⁻¹ appeared.

GPC; There were not detected the stating materials, i.e., the secondaryalkylamine having a fluoroalkyl ether group and methyl 6-iodohexanoate.

FD-MS; A parent peak appeared at a m/e ratio of 1,530.

EXAMPLE 20 ##STR38##

In a 1-liter flask equipped with an agitating blade and a droppingfunnel were placed 21.2 g (0.10 mole) of trimellitic anhydride chlorideand 300 ml of anhydrous pyridine, and cooled to 5° C. or lower. Then, asolution of 64.8 g (0.10 mole) of an alcohol having a fluoroalkyl ethergroup represented by the formula F--CF(CF₃)CF₂ O]₃ CF(CF₃)CH₂ OH in 300ml of anhydrous diethyl ether was added dropwise with stirring over aperiod of about 3 hours to carry out the reaction. After completion ofthe reaction, the reaction solution was washed with 5% hydrochloricacid. Then, it was repeatedly washed with distilled water until the pHof the aqueous layer became 7. The solution thus washed was dried overanhydrous sodium sulfate. Subsequently, the diethyl ether was distilledoff, after which the residue was transferred to a vacuum distillationstill provided with an oil diffusion pump, and the unreacted startingalcohol having a fluoroalkyl ether group was removed under conditions of100° C. and about 1×10⁻³ mmHg to obtain 72.0 g of trimellitic anhydridefluoroalkyl ether ester. In a 1-liter flask equipped with an agitatingblade were placed 72.0 g (0.088 mole) of this product, 23.8 g (0.088mole) of stearyl alcohol and 300 ml of anhydrous benzene, and refluxedwith heating to carry out the reaction. After completion of thereaction, the reaction solution was allowed to stand at room temperaturefor 24 hours to recrystallize the reaction product. The reaction productwas further recrystallized from acetone to obtain a white solid (67 g)having a melting point of 42° C. As a result of IR, GPC and FD-MS, thewhite solid was found to be a mixture of fluorine-containing compoundsof the formulas N and N' which did not contain the starting materialsand any by-product.

IR; There appeared an absorption peak due to carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻¹. An absorptionpeak due to the acid halide at 1,755 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving fluoroalkyl ether group, stearyl alcohol, and chloride oftrimellitic anhydride, and any by-product.

FD-MS; A parent peak appeared at a m/e ratio of 1,093.

EXAMPLE 21 ##STR39##

A wax-like semisolid was obtained by the same production process as inExample 20, except for using as starting materials an alcohol having afluoroalkyl ether group represented by the formula CF₃ O--C₂ F₄ O)_(p)(CF₂ O)_(q) CF₂ CH₂ OH wherein each of p and q is an integer of 1 to 7(average molecular weight: 760), oleyl alcohol, and trimelliticanhydride chloride. As a result of IR, GPC and FD-MS, the wax-likesemisolid was found to be a mixture of fluorine-containing compounds ofthe formulas O and O' which did not contain the starting materials andany by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻¹. An absorptionpeak due to the acid anhydride at 1,755 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group, oleyl alcohol, and chloride oftrimellitic anhydride, and any by-product.

FD-MS; A parent peak appeared at a m/e ratio of 1,200.

EXAMPLE 22 ##STR40##

A wax-like semisolid was obtained by the same production process as inExample 20, except for using as starting materials an alcohol having afluoroalkyl ether group represented by the formula F--CF(CF₃)CF₂ O]_(p)CF(CF₃)CH₂ OCO(CH₂)₃ OH wherein p is an integer of 1 to 15 (averagemolecular weight: 1,390), stearyl alcohol, and trimellitic anhydridechloride. As a result of IR, GPC and FD-MS, the wax-like semisolid wasfound to be a mixture of fluorine-containing compounds of the formulas Pand P' which did not contain the starting materials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻¹. An absorptionpeak due to the acid anhydride at 1,755 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group, stearyl alcohol, and chloride oftrimellitic anhydride, and any by-product.

EXAMPLE 23 ##STR41##

A wax-like semisolid was obtained by the same production process as inExample 20, except for using as starting materials an alcohol having afluoroalkyl ether group represented by the formula F--CF(CF₃)CF₂ O]_(p)CF(CF₃)CO--OC₂ H₄)₄ OH wherein p is an integer of 1 to 15 (averagemolecular weight: 1,330), stearyl alcohol, and trimellitic anhydridechloride. As a result of IR, GPC and FD-MS, the wax-like semisolid wasfound to be a mixture of fluorine-containing compounds of the formulas Qand Q' which did not contain the starting materials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻⁻¹. Anabsorption peak due to the acid anhydride at 1,755 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group, stearyl alcohol, and chloride oftrimellitic anhydride, and any by-product.

EXAMPLE 24

The following fluorine-containing compounds were produced under the sameconditions as in Example 20. ##STR42##

EXAMPLE 25

The following fluorine-containing compounds were produced under the sameconditions as in Example 20. ##STR43##

EXAMPLE 26

The following fluorine-containing compounds were produced under the sameconditions as in Example 20. ##STR44##

EXAMPLE 27

The following fluorine-containing compounds were produced under the sameconditions as in Example 20. ##STR45##

EXAMPLE 28

The following fluorine-containing compounds were produced under the sameconditions as in Example 20. ##STR46##

EXAMPLE 29

The following fluorine-containing compounds were produced under the sameconditions as in Example 20. ##STR47##

EXAMPLE 30

The following fluorine-containing compounds were produced under the sameconditions as in Example 20. ##STR48##

EXAMPLE 31 ##STR49##

In a 1-liter pressure autoclave made of glass having an agitating bladewere placed 81.4 g (0.10 mole) of an alcohol having a fluoroalkyl ethergroup represented by the formula F--CF(CF₃)CF₂ O]₄ CF(CF₃)CH₂ OH and38.5 g (0.10 mole) of octadecylthiomalic anhydride. The air in thesystem was replaced with nitrogen, after which the reaction was carriedout with stirring for 10 hours at 120° C. and at a nitrogen pressure of4 to 5 kg/cm². After completion of the reaction, the reaction mixturewas dissolved in isopropyl ether and the resulting solution was cooledto -10° C. to remove the unreacted octadecylthiomalic anhydride. Then,the residue was transferred to a vacuum distillation still produced withan oil diffusion pump, and the unreacted alcohol having a fluoroalkylether group was removed under conditions of 110° C. and about 1×10⁻³mmHg to obtain 102 g (yield 85%) of a white solid. As a result of IR,GPC and FD-MS, the white solid was found to be a mixture offluorine-containing compounds of the formulas R and R' which did notcontain the starting materials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻⁻¹. Anabsorption peak due to the acid anhydride at 1,755 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group and octadecylthiomalic anhydride.

FD-MS; A parent peak appeared at a m/e ratio of 1,199.

EXAMPLE 32 ##STR50##

In a 1-liter pressure autoclave made of glass having an agitating bladewere placed 138 g (0.10 mole) of an alcohol having a fluoroalkyl ethergroup represented by the formula F--CF(CF₃)CF₂ O]_(p) CF(CF₃)CON(CH₃)C₂H₄ OH wherein p is an integer of 1 to 15 (average molecular weight:1,380) and 27.2 g (0.10 mole) of decylthiomalic anhydride. The air inthe system was replaced with nitrogen, after which the reaction wascarried out with stirring for 5 hours at 140° C. and at a nitrogenpressure of 9 to 10 kg/cm². After completion of the reaction, the samepurifying treatment as in Example 31 was carried out to obtain 129 g(yield 78%) of a milk-white colloidal liquid. As a result of IR, GPC andFD-MS, the milk-white colloidal liquid was found to be a mixture offluorine-containing compounds of the formulas S and S' which did notcontain the starting materials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻⁻¹. Anabsorption peak due to the acid halide at 1,755 cm⁻¹ disappeared.

GPC; There were not detected the starting materials i.e., the alcoholhaving a fluoroalkyl ether group and decylthiomalic anhydride.

FD-MS; A parent peak appeared at a m/e ratio of 1,650.

EXAMPLE 33 ##STR51##

There was obtained about 204 g (yield 72%) of a milk-white colloidalliquid by the same production process as in Example 31, except for using248 g (0.10 mole) of an alcohol having a fluoroalkyl ether grouprepresented by the formula F--C₃ F₆ O)_(p) C₂ F₄ CH₂ OH wherein p is aninteger of 1 to 15 (average molecular weight: 2,480) and 35.7 g (0.10mole) of hexadecylthiomalic anhydride as starting materials. As a resultof IR, GPC and FD-MS, the milk-white colloidal liquid was found to be amixture of fluorine-containing compounds of the formulas T and T' whichdid not contain the starting materials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻⁻¹. Anabsorption peak due to the acid anhydride at 1,755 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group and hexadecylthiomalic anhydride.

FD-MS; A parent peak appeared at a m/e ratio of 2,840.

EXAMPLE 34 ##STR52##

There was obtained 134 g (yield 83%) of a milk-white colloidal liquid bythe same production process as in Example 31, except for using 128 g(0.10 mole) of an alcohol having a fluoroalkyl ether group representedby the formula CClF₂ O--CF₂ CF(CF₃)O]_(p)[CF₂ O]_(g) CF₂ CH₂ OH whereineach of p and q is an integer of 1 to 15 (average molecular weight:1,280) and 32.9 g (0.10 mole) of tetradecylthiomalic anhydride asstarting materials. As a result of IR, GPC and FD-MS, the milk-whitecolloidal liquid was found to be a mixture of fluorine-containingcompounds of the formulas U and U' which did not contain the startingmaterials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻⁻¹. Anabsorption peak due to the acid halide at 1,755 cm⁻¹ disappeared.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group and tetradecylthiomalic anhydride.

FD-MS; A parent peak appeared at a m/e ratio of 1,610.

EXAMPLE 35

The following fluorine-containing compounds were produced under the sameconditions as in Example 31. ##STR53##

EXAMPLE 36

The following fluorine-containing compounds were produced under the sameconditions as in Example 31. ##STR54##

EXAMPLE 37

The following fluorine-containing compounds were produced under the sameconditions as in Example 31. ##STR55##

EXAMPLE 38 ##STR56##

In a 1-liter flask equipped with an agitating blade were placed 79.0 g(0.10 mole) of an acrylate having a fluoroalkyl ether group representedby the formula CF₃ O--CF₂ CF(CF₃)O]_(p) [CF₂ O]_(q) CF₂ CH₂ OCOCH═CH₂wherein each of p and q is an integer of 1 to 9 (average molecularweight: 790), 26.0 g (0.10 mole) of α-mercaptomyristic acid, 50 g ofsodium acetate, 1 g of hydroquinone and 300 ml of 95% ethanol. They weresubjected to addition reaction by continuing refluxing with heating for6 hours. After completion of the reaction, the ethanol and the unreactedacrylate having a fluoroalkyl ether group were removed by vacuumdistillation. Distilled water was added to the residue and the reactionproduct was extracted and purified with isopropyl ether to obtain 86 gof a white solid having a melting point of 35° C. As a result of IR, GPCand FD-MS, the white solid was found to be a fluorine-containingcompound of the formula V which did not contain the starting materialsand any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻⁻¹. Theredisappeared an absorption peak due to the thiol at 2,600 cm⁻¹ and anabsorption peak due to a carbon-carbon double bond at 1,640 cm⁻¹.

GPC; There were not detected the starting materials, i.e., the alcoholhaving a fluoroalkyl ether group and α-mercaptomyristic acid.

FD-MS; A parent peak appeared at a m/e ratio of 1,050.

EXAMPLE 39 ##STR57##

In a 1-liter flask equipped with an agitating blade were placed 70.2 g(0.10 mole) of an acrylate having a fluoroalkyl ether group representedby the formula F--CF(CF₃)CF₂ O]₃ CF(CF₃)CH₂ OCOCH═CH₂ (molecular weight:702), 31.7 g (0.10 mole) of α-mercaptostearic acid, 50 g of sodiumacetate, 1 g of hydroquinone and 300 ml of 95% ethanol. They weresubjected to addition reaction by continuing refluxing with heating for4 hours. After completion of the reaction, the same purifying treatmentas in Example 38 was carried out to obtain 81 g of a white solid havinga melting point of 79° C. As a result of IR, GPC and FD-MS, the whitesolid was found to be a fluorine-containing compound of the formula Wwhich did not contain the starting materials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻⁻¹. Theredisappeared an absorption peak due to the thiol at 2,600 cm⁻¹ and anabsorption peak due to a carbon-carbon double bond at 1,640 cm⁻¹.

GPC; There were not detected the starting materials, i.e., the acrylatehaving a fluoroalkyl ether group and α-mercaptostearic acid.

FD-MS; A parent peak appeared at a m/e ratio of 1,019.

EXAMPLE 40 ##STR58##

There was obtained 125 g of a wax-like semisolid by the same productionprocess as in Example 38, except for using 138 g (0.10 mole) of anacrylate having a fluoroalkyl ether group represented by the formulaF--CF(CF₃)CF₂ O]_(p) CF(CF₃)CO--OC₂ H₄)₄ OCOCH═CH₂ wherein p is aninteger of 1 to 15 (average molecular weight: 1,380) and 31.7 g (0.10mole) of α-mercaptostearic acid as starting materials. As a result ofIR, GPC and FD-MS, the wax-like semisolid was found to be afluorine-containing compound of the formula X which did not contain thestarting materials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹, an absorption peak due to an ester at 1,755 cm⁻⁻¹. Theredisappeared an absorption peak due to the thiol at 2,600 cm⁻¹ and anabsorption peak due to a carbon-carbon double bond at 1,640 cm⁻¹.

GPC; There were not detected the starting materials, i.e., the acrylatehaving a fluoroalkyl ether group and α-mercaptostearic acid.

FD-MS; A parent peak appeared at a m/e ratio of 1,700.

EXAMPLE 41 ##STR59##

There was obtained 142 g of a wax-like semisolid by the same productionprocess as in Example 38, except for using 133 g (0.10 mole) of anacrylate having a fluoroalkyl ether group represented by the formulaCClF₂ O--CF₂ CF(CF₃)O]_(p) [CF₂ O]CF₂ CH₂ OCOCH═CH₂ wherein each of pand q is an integer of 1 to 15 (average molecular weight: 1,330) and31.7 g (0.10 mole) of α-mercaptostearic acid as starting materials. As aresult of IR, GPC and FD-MS, the wax-like semisolid was found to be afluorine-containing compound of the formula Y which did not contain thestarting materials and any by-product.

IR; There appeared an absorption peak due to a carboxylic acid at 1,705cm⁻¹ and an absorption peak due to an ester at 1,755 cm⁻⁻¹. Theredisappeared an absorption peak due to the thiol at 2,600 cm⁻¹ and anabsorption peak due to a carbon-carbon double bond at 1,640 cm⁻¹.

GPC; There were not detected the starting materials, i.e., the acrylatehaving a fluoroalkyl ether group and α-mercaptostearic acid.

FD-MS; A parent peak appeared at a m/e ratio of 1,650.

EXAMPLE 42

The following fluorine-containing compound was produced under the sameconditions as in Example 38. ##STR60##

EXAMPLE 43

The following fluorine-containing compound was produced under the sameconditions as in Example 38. ##STR61##

EXAMPLE 44

The following fluorine-containing compound was produced under the sameconditions as in Example 38. ##STR62##

EXAMPLE 45

The following fluorine-containing compound was produced under the sameconditions as in Example 38. ##STR63##

EXAMPLE 46

The following fluorine-containing compound was produced under the sameconditions as in Example 38. ##STR64##

EXAMPLE 47

The following fluorine-containing compound was produced under the sameconditions as in Example 38. ##STR65##

EXAMPLE 48

The following fluorine-containing compound was produced under the sameconditions as in Example 38. ##STR66##

EXAMPLE 49

The following fluorine-containing compound was produced under the sameconditions as in Example 38. ##STR67##

EXAMPLES 50 TO 110

There was use a non-magnetic substrate composed of a polyester film andsteep hill-shaped protuberances formed on the surface of the film in anumber 1×10⁷ per mm² : in the polyester film granular protuberances witha gentle slope (average height 70 Å, diameter 1 μm) formed by silicaparticles contained in the polyester film were present in a number ofseveral protuberances per 100 μm² of the film surface, and relativelylarge protruberances formed by fine particles attributable to theresidue of a polymerization catalyst had been reduced as such aspossible; and the hill-shaped protuberances had been formed by usingsilica colloidal particles having a diameter of 150 Å as cores and aultraviolet-curable epoxy resin as a binder. A thin Co-Ni ferromagneticmetal film (Ni content 20%, film thickness 1000 Å) was formed on thesubstrate in the presence of a slight amount of oxygen by a continuousvacuum oblique deposition method. The oxygen content of the thin filmwas 5% in terms of atomic fraction.

Each of the above-mentioned fluorine-containing compounds of the presentinvention or a mixture of the compound and a conventional lubricant wasapplied on the thin metal film in an amount of 10 mg per m² of thesurface of the thin metal film to form a lubricant layer. Then, thesubstrate thus treated was cut into a predetermined width to form amagnetic tape. Each of the magnetic tapes thus obtained was set in acommercially available video deck and its output characteristics duringrepeated running were measured in circumstances of 23° C. and 5% RH. Indetail, there was counted the number of runnings which could beconducted until the RF output became lower than its initial value by 3dB or the output began to vary. Table 1 shows the results obtained. Thefluorine-containing compounds of the present invention used are denotedin Table 1 by the above example numbers. Table 1 also shows themeasurement results obtained in the case of forming a lubricant layer bythe use of a mixture of the fluorine-containing compound of the presentinvention and a conventional lubricant.

From Table 1, it can be seen that all of the magnetic tape sampleshaving a lubricant layer comprising the fluorine-containing compound ofthe present invention are excellent in durability in repeated running ata low humidity. On the other hand, as shown for Comparative Examples 1to 5, the magnetic tape samples having a lubricant layer comprising aconventional lubricant alone are poor in durability at a low humidity.

                                      TABLE 1                                     __________________________________________________________________________           Composition of lubricant layer                                                                            The number of                                     Compound                    repetitions of                                    of the                                                                              Conventional      Mixing                                                                            running which                              Magnetic                                                                             invention                                                                           lubricant         ratio                                                                             a magnetic                                 tape   (A)   (B)               (A):(B)                                                                           tape endured                               __________________________________________________________________________    Example 50                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 1                                                              Example 51                                                                           Compound obtained in Example 1                                                       ##STR68##        2:1 200 times or more                          Example 52                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 2                                                              Example 53                                                                           Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 200 times                                         obtained in                 or more                                           Example 2                                                              Example 54                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 3                                                              Example 55                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 4                                                              Example 56                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 5                                                              Example 57                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 6                                                              Example 58                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 7                                                              Example 59                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 8                                                              Example 60                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 9                                                              Example 61                                                                           Compound obtained in Example 9                                                       ##STR69##        2:1 200 times or more                          Example 62                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 10                                                             Example 63                                                                           Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 200 times                                         obtained in                 or more                                           Example 10                                                             Example 64                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 11                                                             Example 65                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 12                                                             Example 66                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 13                                                             Example 67                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 14                                                             Example 68                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 15                                                             Example 69                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 16                                                             Example 70                                                                           Compound obtained in Example 16                                                      ##STR70##        2:1 200 times or more                          Example 71                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 17                                                             Example 72                                                                           Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 200 times                                         obtained in                 or more                                           Example 17                                                             Example 73                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 18                                                             Example 74                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 19                                                             Example 75                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 20                                                             Example 76                                                                           Compound obtained in Example 20                                                      ##STR71##        2:1 200 times or more                          Example 77                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 21                                                             Example 78                                                                           Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 200 times                                         obtained in                 or more                                           Example 21                                                             Example 79                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 22                                                             Example 80                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 23                                                             Example 81                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 24                                                             Example 82                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 25                                                             Example 83                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 26                                                             Example 84                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 27                                                             Example 85                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 28                                                             Example 86                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 29                                                             Example 87                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 30                                                             Example 88                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 31                                                             Example 89                                                                           Compound obtained in Example 31                                                      ##STR72##        2:1 200 times or more                          Example 90                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 32                                                             Example 91                                                                           Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 200 times                                         obtained in                 or more                                           Example 32                                                             Example 92                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 33                                                             Example 93                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 34                                                             Example 94                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 35                                                             Example 95                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 36                                                             Example 96                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 37                                                             Example 97                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 38                                                             Example 98                                                                           Compound obtained in Example 38                                                      ##STR73##        2:1 200 times or more                          Example 99                                                                           Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 39                                                             Example 100                                                                          Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 200 times                                         obtained in                 or more                                           Example 39                                                             Example 101                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 40                                                             Example 102                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 41                                                             Example 103                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 42                                                             Example 104                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 43                                                             Example 105                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 44                                                             Example 106                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 45                                                             Example 107                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 46                                                             Example 108                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 47                                                             Example 109                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 48                                                             Example 110                                                                          Compound                                                                            --                --  200 times                                         obtained in                 or more                                           Example 49                                                             Comparative Example 1                                                                --                                                                                   ##STR74##        --  20 times                                   Comparative                                                                          --    C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           --  33 times                                   Example 2                                                                     Comparative Example 3                                                                --                                                                                   ##STR75##        --  57 times                                   Comparative Example 4                                                                --                                                                                   ##STR76##        --  50 times                                   Comparative Example 5                                                                --                                                                                   ##STR77##        --  92 times                                   __________________________________________________________________________

EXAMPLES 111 TO 171

A plated non-magnetic Ni-P alloy film of 25 μm in thickness was formedon the surface of an Al alloy plate having a diameter of 95 mm and athickness of 1.2 mm, and protuberances were formed in the surface of thefilm by texturing so as to adjust the average roughness of the surfaceto 50 Å and the maximum height of the protuberances to 300 Å, whereby anon-magnetic substrate was obtained. A Cr primer layer of 1,300 Å inthickness and a thin Co-Ni ferromagnetic metal film of 600 Å inthickness were formed on the substrate by sputtering. A graphiteprotective layer of 200 Å in thickness was further formed on the thinmetal film by sputtering. Thus, sample A was obtained. Sample B wasobtained in the same manner as above except for forming a diamond-likecarbon protective layer of 50 Å in thickness by plasma CVD in place ofthe graphite protective layer. Each of the above-mentionedfluorine-containing compounds of the present invention or a mixture ofthe compound and a conventional lubricant was applied on the protectivelayer of each of these samples in an amount of 10 mg per m² of thesurface of the protective layer to form a lubricant layer. The magneticdiscs thus obtained were subjected to a CSS endurance test incircumstances of 23° C. and 5% RH, and the durability was judged by thenumber of times of CSS at the time when the coefficient of frictionexceeded 1.0 or when head crush occurred. Table 2 shows the resultsobtained. The fluorine-containing compounds of the present inventionused are denoted in Table 2 by the above example numbers. Table 2 alsoshows the test results obtained in the case of forming a lubricant layerby the use of a mixture of the fluorine-containing compound of thepresent invention and a conventional lubricant.

From Table 2, it can be seen that all of the magnetic disc sampleshaving a lubricant layer comprising the fluorine-containing compound ofthe present invention are excellent in CSS durability at a low humidity.On the other hand, as shown for Comparative Examples 6 to 10, magneticdisc samples having a lubricant layer comprising a conventionallubricant alone are poor in durability at a low humidity.

                                      TABLE 2                                     __________________________________________________________________________           Composition of lubricant layer  The number of                                 Compound                        repetitions of                                of the                                                                              Conventional      Mixing  CSS which a                            Magnetic                                                                             invention                                                                           lubricant         ratio   magnetic disc                          disc   (A)   (B)               (A):(B)                                                                           Sample                                                                            endured                                __________________________________________________________________________    Example 111                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 1                                                              Example 112                                                                          Compound obtained in Example 1                                                       ##STR78##        2:1 B   50,000 times or more                   Example 113                                                                          Compound                                                                            --                --  B   50,000 times                                  obtained in                     or more                                       Example 2                                                              Example 114                                                                          Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 A   50,000 times                                  obtained in                     or more                                       Example 2                                                              Example 115                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 3                                                              Example 116                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 4                                                              Example 117                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 5                                                              Example 118                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 6                                                              Example 119                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 7                                                              Example 120                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 8                                                              Example 121                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 9                                                              Example 122                                                                          Compound obtained in Example 9                                                       ##STR79##        2:1 B   50,000 times or more                   Example 123                                                                          Compound                                                                            --                --  B   50,000 times                                  obtained in                     or more                                       Example 10                                                             Example 124                                                                          Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 A   50,000 times                                  obtained in                     or more                                       Example 10                                                             Example 125                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 11                                                             Example 126                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 12                                                             Example 127                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 13                                                             Example 128                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 14                                                             Example 129                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 15                                                             Example 130                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 16                                                             Example 131                                                                          Compound obtained in Example 16                                                      ##STR80##        2:1 B   50,000 times or more                   Example 132                                                                          Compound                                                                            --                --  B   50,000 times                                  obtained in                     or more                                       Example 17                                                             Example 133                                                                          Compound                                                                            C.sub.17 H.sub. 35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                          1:1 A   50,000 times                                  obtained in                     or more                                       Example 17                                                             Example 134                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 18                                                             Example 135                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 19                                                             Example 136                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 20                                                             Example 137                                                                          Compound obtained in Example 20                                                      ##STR81##        2:1 B   50,000 times or more                   Example 138                                                                          Compound                                                                            --                --  B   50,000 times                                  obtained in                     or more                                       Example 21                                                             Example 139                                                                          Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 A   50,000 times                                  obtained in                     or more                                       Example 21                                                             Example 140                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 22                                                             Example 141                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 23                                                             Example 142                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 24                                                             Example 143                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 25                                                             Example 144                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 26                                                             Example 145                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 27                                                             Example 146                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 28                                                             Example 147                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 29                                                             Example 148                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 30                                                             Example 149                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 31                                                             Example 150                                                                          Compound obtained in Example 31                                                      ##STR82##        2:1 B   50,000 times or more                   Example 151                                                                          Compound                                                                            --                --  B   50,000 times                                  obtained in                     or more                                       Example 32                                                             Example 152                                                                          Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 A   50,000 times                                  obtained in                     or more                                       Example 32                                                             Example 153                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 33                                                             Example 154                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 34                                                             Example 155                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 35                                                             Example 156                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 36                                                             Example 157                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 37                                                             Example 158                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 38                                                             Example 159                                                                          Compound obtained in Example 38                                                      ##STR83##        2:1 B   50,000 times or more                   Example 160                                                                          Compound                                                                            --                --  B   50,000 times                                  obtained in                     or more                                       Example 39                                                             Example 161                                                                          Compound                                                                            C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           1:1 A   50,000 times                                  obtained in                     or more                                       Example 39                                                             Example 162                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 40                                                             Example 163                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 41                                                             Example 164                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 42                                                             Example 165                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 43                                                             Example 166                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 44                                                             Example 167                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 45                                                             Example 168                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 46                                                             Example 169                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 47                                                             Example 170                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 48                                                             Example 171                                                                          Compound                                                                            --                --  A   50,000 times                                  obtained in                     or more                                       Example 49                                                             Comparative Example 6                                                                --                                                                                   ##STR84##        --  A   Crushed by 5,000 repetitions           Comparative                                                                          --    C.sub.17 H.sub.35 COOC.sub.2 H.sub.4 C.sub.8 F.sub.17                                           --  A   Crushed by                             Example 7                              5,000                                                                         repetitions                            Comparative Example 8                                                                --                                                                                   ##STR85##        --  A   10,000 times                           Comparative Example 9                                                                --                                                                                   ##STR86##        --  A    8,000 times                           Comparative Example 10                                                               --                                                                                   ##STR87##        --  A   20,000 times                           __________________________________________________________________________

What is claimed is:
 1. A fluorine-containing compound represented by theformula: ##STR88## wherein R_(f) is a fluoroalkyl ether end group having5 to 50 carbon atoms, R₁ is an aliphatic alkyl end group or an aliphaticalkenyl end group, R'''₂ is an aliphatic alkylene group, and R₄ is analiphatic alkylene group having no or one or more carbon atoms.